Motor control valve with flow restrictor means



G. J. MARTIN MOTOR CONTROL VALVE WITH FLOW RESTRICTOR MEANS Filed Oct. 30, 1963 INVENTOR.

GEORGE J. MARTIN akgy ATTORNEYS United States Patent 3,247,867. MOTOR CONTROL VALVE WlTH FLOW RESTRHCTQR MEANS George J. Martin, Lyndhurst, Uhio, assignor to Parker- Hannifin Corporation, Cleveland, Ohio, a corporation of Ohio Filed Oct. 30, 1963, Ser. No. 324L049 3 Claims. (Cl. 137-5962) The present invention relates generally as indicated to a valve with flow restrictor means and more particularly to a directional control valve for a fluid motor in which the flow of fluid to and from the motor is controlled via a two-way restrictor in the housing of the directional control valve.

It is a principal object of this invention to provide a valve with flow restrictor means which provides for equal or different magnitudes of flow restriction in opposite directions.

It is another object of this invention to provide a two- Way restrictor for a directional control valve which is in the form of a pressure-actuated member alternately engageable with seats on opposite sides thereof and defining with said seats flow restricting orifices which are of equal or different sizes as desired.

It is another object of this invention to provide a two- Way flow restrictor of the character referred to which is disposed on the downstream side of a load check valve of a directional control valve, the check valve being arranged to be unseated in normal manner by fluid pressure on its upstream side, and to be mechanicallyunseated by a fluid pressure actuated plunger to permit reverse flow therethrough.

It is another object of this invention to provide a simple unitary two-way restrictor which is replaceably mounted in the motor port bushing of a directional control valve.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features herein after fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the vvarious ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a top plan view of one embodiment of the present invention;

FIG. 2 is a cross-section view taken substantially along the line 22, FIG. 1;

FIG. 3 is a fragmentary cross-section view taken substantially along the line 33, FIG. 1; and

FIG. 4 is a perspective view, on enlarged scale, of a preferred form of flow restrictor.

As shown in the drawing, the directional control valve 1 comprises a housing 2 having a pressure inlet port 3 for connection with a fluid pressure source, such as a pump, not shown; a return port 4- for connection with a fluid reservoir, not shown; and a cylinder port 5 for connection with the port of a single acting cylinder 6. As best shown in FIG. 2, the housing 2 is cored to provide a series of passages therein that intersect the bore 7 at axially spaced intervals therealong, to wit, inlet passages 8, 8 from inlet port 3 straddling the middle return passage 9 to return port 4, cylinder passages 10, 10 which straddle the aforesaid inlet passages 8, 8, and top and bottom return passages 9, 9 which, in turn, straddle the cylinder passages 10, 10. Between the inlet chamber 11 and the bottom return passage 9 is a relief valve 12 which opens communication between the inlet port 3 and the return port 4 when the pressure in the inlet chamber 11 exceeds that for which the relief valve 12 is set.

Reciprocablein the bore 7 of housing 2 is a valve spool 14 which is held in the neutral position as shown by a spring centering mechanism 15 at the upper end of the spool. The spool 14 has alternate lands and grooves cooperating with the aforementioned passages 8, 9, and iii in a manner hereinafter explained in detail.

When the spool 7 is in the neutral or inactive position, as shown in FIG. 2, fluid flows freely from the inlet port 3 to the return port 4 via the then intercommunicating inlet passage 8 and middle return passage 9, whereby the pump connected to the inlet port 3 operates under substantially no load.

Referring now to FIG. 3, the housing has another bore 16 alongside and parallel to the spool bore '7 to which the upper and lower cylinder passages 11), 10 lead. In the lower portion of the bore 16 there is a plunger 17 which is moved upwardly by fluid pressure in the lower cylinder passage 10 and downwardly (to the position shown) by fluid pressure in the upper cylinder passage 10. In the portion of the bore 16 above plunger 17 is a tubular check valve seat and guide member 18 pressfitted or otherwise secured therein. A check valve 19 is yieldably urged into engagement with member 18 by spring 20, the upper end of spring 20 being engaged with a spring backup member 21 which is seated in the bushing or adaptor 23 screwed into the housing 2 the bushing providing the aforesaid cylinder port 5. When the spool 14 is in its neutral position, the check valve 19 constitutes a so-called load check which prevents flow of fluid from the cylinder 6 to the upper cylinder passage 10 and thus the piston 24 cannot move in upward direction as viewed in FIG. 3 so long as the check valve 19 is closed. However, when it is desired to permit upward movement of the piston 24 means must be provided for opening the check valve 19, and in the present case, that means constitutes a rod-like extension 25 of the plunger 17 which engages and moves the check valve 19 upwardly away from its seat when fluid under pressure in the lower cylinder passage 10 moves the plunger 17 upwardly.

Axially movable in the space between the spring backup member 2 1 and the cylinder port bushing 23 is a two-way restrictor 26 herein shown as comprising a noncircular part guided in the counterbore 27 of the cylinder port bushing 23. Said restrictor 26 has recesses 28 and 29 in its opposite end faces, the latter each having at least one groove or channel 30 and 31 leading from the respective recesses 28 and 29 to't-he periphery of the restrictor 2 6. As a matter of convenience and economy of manufacture, the restrictor 26 herein is shown as being made of hex stock (see FIG. 4) with the channels 30 and 31 leading from the respective recesses 28 and 2.9 to the flat sides of the hex. As hereinafter explained, the channels 30 and 31 alternately constitute flow restricting orifices and it is to be understood that the channels 3i? and 31 may be of equal or unequal size to provide equal or different restrictions of flow in opposite directions.

Thus, when the spool 14 is moved downwardly from the position shown in FIG. 2, the land 32 thereof closes fluid communication between both inlet passages 8, 8 and the middle return passage 9, and opens fluid communication between the upper inlet passage 8 and the upper cylinder passage while the land 34 closes fluid communication between the upper cylinder passage 10 and the upper return passage 9 and the land 35 opens fluid communication between the lower cylinder passage 10 and the lower return passage 9. Referring to FIG. 3, fluid under pressure in the upper cylinder passage 10 acts on the upper end of the plunger 17 and holds it in its down position, and forces the check valve 19 upwardly out of engagement with its seat, and as the fluid under pressure flows through the central opening in the spring backup member 21, the flow restrictor 26 is forced upwardly into engagement with the seat 36 in the cylinder port bushing 23. With the restrictor 26 thus seated,-

fluid can flow into the upper end of the cylinder 6 only through the upper groove 30, and thus the rate of downward movement of the piston 24 is controlled by the size of the upper groove 30. When the spool 14 is permitted to return to its neutral position by the action of the centering spring mechanism 15, the piston 24 is locked against upward movement by the closing of the check valve 19.

Now, when the spool 14 is shifted upwardly from its FIG. 2 neutral position, again the land 32 of the spool and, in addition, the land 37 thereof, closes communication between both inlet passages 8, 8 and the middle return passage 9, the land 37 also being operative to open fluid communication between the lower inlet passage 8 and the lower cylinder passage 10, and thus when fluid pressure builds up in the lower cylinder passage 10 it will act on the lower end of the plunger 17 to urge the latter upwardly until its extension engages and lifts the check valve 19 away from its seat. At the same time, the land 34 opens fluid communication between the upper cylinder passage 10 and the upper return passage 9, whereby fluid is returned through return port 4 to a reservoir from the cylinder 6 through the now open check-valve 19. However, the flow of fluid from the cylinder 6 into the cylinder port 5 forces the restrictor 26 downwardly against the seat 38 of the backup member 21 whereby all of the returning fluid must pass through the lower restrictor groove 31, and that rate of flow may be the same as, greater than, or less than, the rate of flow through the upper groove which restricts flow of fluid in the opposite direction.

Although by way of illustrative example only, the twoway restrictor 26 herein is shown in a spool valve 1 for controlling the actuation of a single acting fluid motor 6, it is to be understood that the present invention has equal applicability in connection with double acting fluid motors simply by forming a second cylinder port in the boss 39 of the housing 2 communicating with the lower cylinder passage 10 so that when the lower cylinder passage 10 is communicated with the lower inlet passage 8, the piston 24 in the cylinder will be moved by fluid pressure in the opposite direction from that in which it is moved by fluid under pressure in the upper cylinder passage 10 when communicated with the cylinder port 5. It is also obvious that in such double acting arrangement, the bore 16 may be extended downwardly for installation of another load check valve 19, and another cylinder port bushing 23. In such case, a second restrictor 26 would not be required, since flow in both directions is already restricted by the upper restrictor 26, but the plunger 17 will have a downwardly extending rod-like extension 25 for opening of the lower check valve 19 upon downward movement of said plunger 17.

Grooves 30, 31 provide for a self-cleaning action. Thus, if the operator moves spool 14 downwardly to connect upper cylinder passage 10 with inlet passage 8 for causing pressure fluid to flow past restrictor 26 into cylinder 6 for extending piston 24 and a dirt particle enters grooves 30 in the restrictor to block such flow, the operator will be aware of this fact when piston 24 fails to move .to extended position. The operator may then momentarily move spool 14 upwardly to connect upper cylinder passage 10 with the upper branch of exhaust passage 9 to permit reverse flow of fluid from cylinder 6 past restrictor 26 and to exhaust port 4. This reversal of fluid flow. causes restrictor 26 to move downwardly away from seat 36 and give the fluid a chance to wash the dirt particle out of groove 30. The operator may then reposition spool 14 for extending piston 24.

Recesses 28, 29 are formed to a standard preselected depth in restrictor 26 and grooves 30, 31 are thereafter formed of selected widths and depths to provide the desired flow rate in the particular valve in which the restrictor 26 is to be assembled. Such preselected depth for recesses 28, 29 is the same or greater than the maximum depth of the respective grooves 30, 31 so that any semi-finished restrictor 26 may be taken from the shelf and have grooves 30, 31 formed therein of a size to suit the particular requirement. Because the recesses 28, 29 are deeper than, or at least as deep as, the respective grooves 30, 31, the latter are of constant length so that the flow rates therethrough are controlled solely by width and depth.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. In a valve assembly for controlling actuation of a fluid motor, the combination of a housing having an inlet port for connection with a fluid pressure source, a return port for connection with a fluid reservoir, and at least one motor port for connection with a fluid motor; a valve member movable in said housing from an inactive position to either of two operating positions whereat said motor port is selectively communicated with said inlet port and said return port via a passage in said housing extending from said valve member to said motor port; a check valve in said passage opened by flow of fluid under pressure in said passage from said valve member to said motor port; a fluid pressure actuated member in said housing moved by fluid under pressure acting thereon to open said check valve to permit flow of fluid in said passage in the opposite direction from said motor port to said valve member; and two-way flow restrictor means in said passage defining therewith first and second restricted passages which respectively restrict flow of fluid in opposite directions only according to the relative flow capacities of said first and second passages, said restrictor means comprising a plate-like means movable in said passage with its opposite end faces alternately engaging spaced apart seats in said passage, said end faces having grooves therein constituting the respective first and second passages when engaged with the respective seats.

2. In combination, a valve housing having a passage through which fluid flows in opposite directions; said passage being laterally enlarged to provide spaced apart seats; a restrictor means movable in said passage having opposite end faces alternately engaging said seats; said respective seats and end faces, when engaged, defining first and second restricted passage means which respectively restrict flow of fluid in opposite directions only according to the relative flow capacities of said first and second passage means; a spring seated check valve means disposed in said passage having a spring back up means constituting one of said seats, said seated check valve means being adapted to be moved by fluid pressure to an open position permitting flow of fluid in one direction, and means adapted to be moved into engagement with said check valve means to move it to such open position permitting flow of fluid in the opposite direction. 5 3. The combination of claim 2 wherein a port means detachably connected to said housing contains the other one of said seats whereby, upon detachment of said port means, said restrictor means, back up means, and check valve means may be removed from said housing. 10

References Cited by the Examiner UNITED STATES PATENTS 798,057 8/1905 Nielsen 137-540 X 15 Steedman 91443 Blackburn 137-5135 Forman 91-443 X Heigis et al. 137540 X Finlayson 91-420 X Hubert et al. 91--420 Dickert et a1 137512 X Kesselbr'ing 137493.8 X

MARTIN P. SCHWADRON, Acting Primary Examiner.

M. CARY NELSON, Examiner. 

1. IN A VALVE ASSEMBLY FOR CONTROLLING ACTUATION OF A FLUID MOTOR, THE COMBINATION OF A HOUSING HAVING AN INLET PORT FOR CONNECTION WITH A FLUID PRESSURE SOURCE, A RETURN PORT FOR CONNECTION WITH A FLUID RESERVOIR, AND AT LEAST ONE MOTOR PORT FOR CONNECTION WITH A FLUID MOTOR; A VALVE MEMBER MOVABLE IN SAID HOUSING FROM AN INACTIVE POSITION TO EITHER OF TWO OPERATING POSITIONS WHEREAT SAID MOTOR PORT IS SELECTIVELY COMMUNICATED WITH SAID INLET PORT AND SAID RETURN PORT VIA A PASSAGE IN SAID HOUSING EXTENDING FROM SAID VALVE MEMBER TO SAID MOTOR PORT; A CHECK VALVE IN SAID PASSAGE OPENED BY FLOW OF FLUID UNDER PRESSURE IN SAID PASSAGE FROM SAID VALVE MEMBER TO SAID MOTOR PORT; A FLUID PRESSURE ACTUATED MEMBER IN SAID HOUSING MOVED BY FLUID UNDER PRESSURE ACTING THEREON TO OPEN SAID CHECK VALVE TO PERMIT FLOW OF FLUID IN SAID PASSAGE IN THE OPPOSITE DIRECTION FROM SAID MOTOR PORT TO SAID VALVE MEMBER; AND TWO-WAY FLOW RESISTOR MEANS IN SAID PASSAGE WHICH DEFINING THEREWITH FIRST AND SECOND RESTRICTED PASSAGES WHICH RESPECTIVELY RESTRICT FLOW OF FLUID IN OPPOSITE DIRECTIONS ONLY ACCORDING TO THE RELATIVE FLOW CAPACITIES OF SAID FIRST AND SECOND PASSAGES, SAID RESTRICTOR MEANS COMPRRISING A PLATE-LIKE MEANS MOVABLE IN SAID PASSAGE WITH ITS OPPOSITE END FACES ALTERNATELY ENGAGING SPACED APART SEATS IN SAID PASSAGE, SAID END FACES HAVING GROOVES THEREIN CONSTITUTING THE RESPECTIE FIRST AND SECOND PASSAGE WHEN ENGAGED WITH THE RESPECTIVE SEATS. 